The departing system, in which Twitter verified notable accounts to confirm their authenticity by adding a blue check mark next to the user’s name, will give way starting April 1 to one in which users must purchase a subscription to be verified, the company has said.

Twitter, which previously didn’t charge for verification, is only providing it now to those who pay $8 to $11 for a monthly subscription, depending on whether it is paid via mobile or web browser.

The revamped subscription program, called Twitter Blue, offers other features including the ability to edit tweets. Elon Musk, who acquired Twitter late last year, said Monday that starting April 15, only verified accounts will be eligible to be promoted in Twitter’s algorithmic recommendations. Such rules are necessary to combat spam bot accounts, he said. After criticism from many users, Mr. Musk announced a modification Tuesday, saying in a tweet that accounts users follow will also be shown in Twitter’s algorithmic feed.

Though some found the previous verification system to be arbitrary and confusing, the process was designed to confirm that public figures’ accounts were legitimate. Over time, the blue check mark evolved into a sought-after marker for many users. The check marks served as a way to combat impersonation and helped make Twitter an attractive communications platform for public personalities.

The new system, which Mr. Musk has said will be fairer than the departing system and is part of his efforts to increase Twitter’s subscription revenue, is inviting a whole new category of complaints, especially from some high-profile accounts.

The “Seinfeld” actor Jason Alexander, who has roughly 732,000 followers on Twitter, said in a recent tweet that he will leave Twitter if he loses his check mark. “Without it, anyone can allege to be me,” he said.

One risk is that Twitter could turn off high-profile users who have long brought star power and influential commentary to the platform.“Those people are like, ‘I’m actually building value for your network, and now you’re making it feel to me that I’m just someone you can charge,’ ” said Jason Goldman, an early Twitter product chief and board member who worked on Twitter’s original verification system.

Twitter introduced verified accounts in 2009 to address concern about impersonation, according to a company blog post from the time. Earlier that year, Tony La Russa, who was then manager of the St. Louis Cardinals, sued Twitter after an impostor account made jokes about the deaths of former major leaguers. Mr. La Russa later dropped the suit, according to a court filing.

Twitter’s rules prohibit impersonation, with exceptions for parody. When Mr. Musk’s Twitter first attempted to relaunch Twitter Blue in November, many users exploited the check marks to pose as celebrities and brands, sowing confusion across the platform. Twitter has since said it has added safeguards meant to combat impersonation, including the requirement that subscribers confirm their phone numbers and avoid changing their profile photos or usernames.

For businesses, Twitter recently launched a subscription program called Verified Organizations, which costs $1,000 monthly, plus $50 monthly for each affiliate account in the U.S., such as for individual employees, according to Twitter’s website. Businesses will receive a gold check mark and square profile image, instead of the typical circle, Twitter said.

Blue check marks “were guardrails to legitimacy; not meaningless status symbols,” tweeted “Star Trek” actor William Shatner, who has 2.5 million Twitter followers. Mr. Shatner said in a recent series of tweets that he was concerned about impersonation, but planned to stay on Twitter for now.

Monica Lewinsky, who has 1.2 million followers on Twitter, complained on Sunday about an account under the username @Monicalewinskai, which is labeled with a check mark because it subscribed to Twitter Blue, according to a notice on the account.

“In what universe is this fair to people who can suffer consequences for being impersonated?” Ms. Lewinsky tweeted. The account now states in its Twitter bio that it is “not actually Monica Lewinsky.”

In response to a query from The Wall Street Journal, the account’s user, who said his name is Aidan but declined to give his last name, said he chose that username because he had used it before in videogames, not because he was trying to impersonate Ms. Lewinsky.

Twitter’s press email responded to a request for comment with an auto reply of a poop emoji.

For many Twitter users, a blue check mark became a coveted symbol, said Matt Navarra, a social-media consultant. “It was an elitist thing. It was a status symbol,” Mr. Navarra said. If everyone can now pay for a blue tick, it will no longer be special, he said.

Still, Mr. Navarra, who writes a newsletter about the social-media industry, said he recently subscribed to the new Twitter Blue so his tweets will be eligible to be boosted by Twitter’s algorithm. “My biggest audience, or following, on social has always been Twitter,” he said.

More social-media companies have begun offering subscriptions, betting that paid features can offer a new revenue stream to help counter a slowdown in digital advertising. Those include Meta Platforms Inc.’s Facebook and Instagram as well as Snap Inc.

Twitter Blue has as many as 525,000 subscribers, according to a recent estimate from Travis Brown, a Berlin-based software developer who tracks social-media platforms.

Many legacy verified users have posted criticism and jokesabout the new subscription programon Twitter, with some saying they no longer want their check marks in part because they disagree with Mr. Musk’s actions and don’t want to be seen as supporting him. “He’s a character that definitely is polarizing,” said Mr. Navarra, the social-media consultant.

Mr. Musk and his supporters argue that Twitter’s legacy check marks were a symbol of classism and they defend the value of the subscription. “There is great wisdom to the old saying: ‘You get what you pay for,’” Mr. Musk tweeted earlier this month.

Taylor Richardson, a college student who has advocated for social-media platforms to verify more Black scientists, said verification helped people get more recognition and a stronger voice on social media. “I don’t plan to pay for something I have earned, proved and continue to work hard for,” she said.